1. Field of the Invention
The present invention relates to a repeating system in an optical pulse code modulation group transmission system using optical fibers.
2. Description of the Prior Art
In conventional high speed PCM transmission systems a sending terminal sends out an input signal information by using a code representing a combination of the presences or absences of pulses, a receiving terminal is provided for regenerating the original information by discriminating the code, and copper cables are used for the transmission lines. This is due to the reason that digital signals should be transmitted with high quality. When transmission is carried out over long distance line 5, repeaters are used per every cable so as to compensate for the current loss in the cable or for equalizing the transmitted signal.
In the above-mentioned PCM transmission system using copper cables, one repeater is required per every one cable, therefore, a group transmission repeating system, wherein the signals transmitted by a plurality of cables are repeated by one single repeater, is not realized.